package com.atguigu.tree;

/**
 * @Author : 孙峰
 * @Description:
 * @Date : 2021/10/6  9:51
 */
public class ArrBinaryTreeDemo {
    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5, 6, 7};

        ArrBinaryTree arrBinaryTree = new ArrBinaryTree(arr);

        arrBinaryTree.preOrder();

    }
}

class ArrBinaryTree {

    private int[] arr;

    public ArrBinaryTree(int[] arr) {
        this.arr = arr;
    }

    public void preOrder() {
        preOrder(0);
    }

    public void preOrder(int index) {

        if (arr == null || arr.length == 0) {
            System.out.println("数组为空，不能按照二叉树前序遍历");
            return;
        }
        System.out.println(arr[index]);

        // 判断当前节点是否有左子节点
        if ((index * 2 + 1) < arr.length) {
            preOrder(index * 2 + 1);
        }
        if ((index * 2 + 2) < arr.length) {
            preOrder(index * 2 + 2);
        }
    }


}